Magnesium alloy is a light weight metallic material which offers good engineering
properties and environmental advantages. Most cast components in this material are
produced by the traditional casting processes, predominantly the die-casting process.
The Expendable Pattern Casting Process (EPC process) is a relatively new casting
process which provides many design, processing and environmental benefits.
However, the process differs significantly from the conventional empty mould sand
casting process and there is the need for research to develop an understanding of the
process parameters.
The research was established to provide a preliminary evaluation of the production of
magnesium base alloy castings by the expendable pattern casting process under gravity
and counter gravity pouring. The major process parameters investigated were filling
pressure, pouring temperature and pattern bead density. The problems experienced in
applying this process for this material in the experimental research were defined.
Microstructures and mechanical properties of the cast specimens were investigated and
reported.
The results showed that the quality of test bar specimens produced by the EPC process
under counter gravity pouring with optimised process parameters was compatible with
the quality of castings produced by the conventional sand casting process.
In addition to the experimental research a review was conducted of the modelling of
different methods of pouring. The pouring methods considered were bottom gating in
gravity pouring, counter gravity pouring in an empty cavity mould process, and
expendable pattern casting processes under both gravity and counter gravity pouring.
A quasi one dimensional fluid mechanics analysis was conducted to explain the effect
of pattern degradation on the delay in mould filling.

Description:

A Master's Thesis. Submitted in partial fulfilment of the requirements for the award of Master of Philosophy of Loughborough University.